ASCII 23
ASCII 23 is End of Transmission Block — the control character ETB.
Every representation
| Character | ETB (not printable) |
| Name | End of Transmission Block |
| Decimal | 23 |
| Hexadecimal | 0x17 |
| Octal | 0027 |
| Binary | 00010111 |
| HTML entity |  |
| Escape sequence | \x17 |
| Unicode | U+0017 |
| Keyboard | Ctrl+W |
| Group | Control character |
What it is for
Ended one block of a message that was split across several transmissions.
Where the number comes from
Codes 0 to 31 were reserved for control: instructions to a teleprinter rather than characters to print. Code 23 is Ctrl+W because the Ctrl key was originally wired to clear the top two bits of whatever you typed, mapping the letter W at 87 down to 23.
Frequently asked questions
What is ASCII 23?
End of Transmission Block (ETB), a control character. In hexadecimal it is 0x17, in octal 0027, and in binary 00010111.
How do I type ASCII 23?
Press Ctrl+W in a terminal. In a string literal you can write it as \\x17 in most languages.
Is ASCII 23 printable?
No. Codes 0 to 31 and 127 are control characters — they were instructions to a teleprinter rather than marks on paper, and most terminals show nothing for them.
Nearby codes
- ASCII 16 — DLE
- ASCII 17 — DC1
- ASCII 18 — DC2
- ASCII 19 — DC3
- ASCII 20 — DC4
- ASCII 21 — NAK
- ASCII 22 — SYN
- ASCII 24 — CAN
- ASCII 25 — EM
- ASCII 26 — SUB
- ASCII 27 — ESC
- ASCII 28 — FS
- ASCII 29 — GS
- ASCII 30 — RS
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